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Also I believe that the fuel pump relays have a inbuilt temp switch. So if there is excessive heat the relay will switch off instead of burning up. So you can limp home instead of being stranded. but like all things mechanical these switches can fail leaving a burnt and charred mess of your relay!
That reads like well-intended mis-information to me because:
1) The fuel relay has no "inbuilt temp switch".
2) If it could "switch off", you couldn't "limp" anywhere with no fuel flowing.
As for the buzzing, check that the relay is earthed properly! Too much resistance in the earth will stop the relay from switching properly.
The fuel relay is "earthed" (grounded) within the ECU, so checking is not withing the scope of the average home mechanic. Nor is such a ground fault known to cause relay buzzing. What is known to cause relay buzzing is a marginal voltage supply to the relay, such as the often-reported age problems with the 25 amp fuse (noted in my post above).
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Bruce Young '93 940-NA (current), 240s (one V8), 140s, 122s, since '63.
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